I was thinking an extra reservoir to keep full or the saw blows up would be an extra pain, and where idiots are concerned, I don't see that being any safer for the saw than having to premix fuel and oil.
When I see people choose one saw vs. another over a single pound of weight difference, I think it makes a third reservoir and oil injection system a non-starter, not even considering the extra cost, complexity, and opportunity for failure. Would you choose the saw that's a pound heavier, a hundred bucks more expensive, and has more to go wrong, or premix the fuel yourself and save the pound and the $$$?